Dual-Parameter and High-Density Sensor Array Based on a-IGZO Thin Film Transistors

Abstract

The skin-like pressure and temperature sensing ability is essential for electronic skin, human–machine interactions and soft robotics. The previous studies have primarily addressed single-point detection of either pressure or temperature, whereas the simultaneous mapping of these parameters still remain challenging. This study introduces a sensor array based on an amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) that can detect pressure (5.29 kPa<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula>, 0.25 to 16 kPa) and temperature (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${0}.{55}\times {10}{^{-{2}}}~{^{\circ }}\text {C}^{-1}$ </tex-math></inline-formula>, 20 to 70 °C) simultaneously and independently. Pressure detection is achieved by a temperature-insensitive piezoresistive film coupled with the gate of TFTs. The temperature is detected by a thermistor diode array in a parallel series, where the diode is formed by connecting the gate and drain of TFTs. The integration of TFTs significantly enhance the spatial resolution of pressure sensor array to 50 pixels per square centimeter (PPSC), surpassing that of human skin (approximately 30 PPSC). The development of this dual-parameter and high-density sensor array has profound significance in electronic skin application.